This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This research involves the study of protein-inhibitor complexes for the purpose of development of novel small molecule inhibitors for the pharmaceutical market. The understanding of detailed interaction between a potential drug molecule (inhibitor) and its target (protein) is critical in the high stakes pharmaceutical industry. The knowledge of the three dimensional molecular structure of these complexes is often a crucial and driving component for the next step medicinal chemical synthesis. We have crystals of various protein-inhibitor complexes, and typically we gain about 0.6 Angstrom increase in resolution using an undulator source as opposed to a rotating anode x-ray source.